U.S. Pat. No. 2,414,459 discloses a fluid fuel burner atomizing the fuel in a thin-walled spray permeable by an airstream supplied to form a combustible mixture. The spray has a hollow frusto-conical form to afford a maximum amount of surface exposure to a surrounding envelope of combustion air. The burner is not cooled and could therefore not be used under high temperature loads.
WO-A-01/55640 describes a burner comprising at least two channels for separate supply of a liquid fuel and an oxygen containing gas. The burner has a twin fluid atomizer head fixed to the discharge end of the burner.
U.S. Pat. No. 3,266,552 describes a burner having a cooling jacket to protect the burner from the heat as created in the interior of a furnace.
To obtain gaseous fuels from solid carbonaceous materials, finely divided solid carbonaceous fuel carried by a gas carrier, for example pulverized coal carried by a gas carrier such as nitrogen gas and/or carbon dioxide, can be partially combusted in a gasification reactor using an oxygen-containing gas. Due to the incomplete combustion, the formed fuel gas is suitable for further combustion. The partial combustion processes can be used, for example for producing pressurized synthesis gas, fuel gas or reducing gas.
In the reactor a flame is maintained by reacting the fuel with the oxygen in the oxygen-containing gas at temperatures above 1300° C. In this reaction carbon monoxide and hydrogenare formed and at some temperatures it is also possible to form methane.
To start-up the gasification reactor, the temperature and the pressure are raised to a level sufficiently high to enable reaction of the fuel with the oxygen-containing gas. For combusting heavy, difficult ignitable fuels, such as pulverized coal, it is common practice to generate a relatively small start-up flame by using a fuel which is less likely to blow out. The small start-up flame is used for ignition of the main fuel flow. Means are needed for igniting the start-up flame and for maintaining a stable flame during temperature and pressure build-up and during ignition of the main fuel flow. If the combustion operation is to be carried out in a closed, confined and pressurized space, such as for example in coal gasification processes, the ignition is normally carried out in two steps. A first ignition flame is generated, which first ignition flame is used to ignite a gaseous or liquid fuel, thereby producing a second larger ignition flame, which in its turn is used to ignite the main fuel flow. The above process for igniting a fuel flow in a pressurized combustion chamber is normally carried out by means of an ignition device and a separate start-up burner operating on gaseous or liquid fuel. The start-up burner is not only used for igniting the main fuel flow but also for pressurizing and heating the combustion chamber before the main fuel is introduced.
It would be an advancement in the art to provide a burner for liquid fuels comprising atomizer units which can be used as a start-up burner for use in a reactor operated at very high temperatures and high pressure loads.